Thanks for the correction Bob. I don't know what made me think it was an on/off oven. The OC-050 datasheet gives a drain of 12 watts in warmup and 4 watts in run mode, so I went with that in the post I just made, calculating the loads, etc.
Bob ----- Original Message ----- > From: Bob Camp <[email protected]> > To: Discussion of precise time and frequency measurement <[email protected]> > Cc: > Sent: Thursday, June 27, 2013 7:27 PM > Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply? > > Hi > > The OCXO in the TBolt has a linear controller. It drops back to about 150 to > 250 > ma on the +12 line after warmup. It's been at least 40 years since I saw an > on/off oven control in production …. > > Remember that the +12 feeds the oscillator circuit. The more crud on the 12 > volts, the worse the phase noise of the output. A linear regulator is a good > idea. > > Bob > > On Jun 27, 2013, at 3:49 PM, Bob Stewart <[email protected]> wrote: > >> Hi Hal and other responders, >> >> I believe that the OCXO uses an ON-OFF type of regulation. So, no, it > doesn't use 1A all the time. Maybe I should just put an ammeter in the line > and see what kind of duty cycle it has after it's at temperature. >> >> >> I tried a 7812 regulator with a small dissipator on it. It goes into > overheat mode almost immediately and the output voltage starts quickly doing > down. The case does have provisions for a single TO-3 transistor conducting > heat to the back of the case with no radiating fins. I had briefly > considered > using a zener and a 2N3055. >> >> I think that instead of worrying this to death, I'm just going to use a > brick to get it together, and then if something comes up later that I like, > I'll put that in. I did like the looks of that PT5102 but it's at end > of life, and 1A is right at it's limit. I've given some consideration > to seeing whether I can pull a few turns off the transformer secondary, as > well. >> >> >> Bob - AE6RV >> >> >> >> ----- Original Message ----- >>> From: Hal Murray <[email protected]> >>> To: Bob Stewart <[email protected]>; Discussion of precise time and > frequency measurement <[email protected]> >>> Cc: [email protected] >>> Sent: Thursday, June 27, 2013 2:24 PM >>> Subject: Re: [time-nuts] +12 Volts 1A (plus a bit) supply? >>> >>> >>> [email protected] said: >>>> The transformer gives me about 20 volts DC out. Dropping 8 volts > at 1 amp >>>> is just a lot of power to void with a resistor. I'd like to > avoid >>> having >>>> that much waste heat in the unit. >>> >>> Does it really take 1A after it's warmed up? >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
